The main objectives of this Neurosciences and Neuropathology Core will be to provide the projects with: a) state of the art analysis of the AD-related pathology in aging models, b) alternative APP tg murine models and c) support in the production and testing of lentiviral vector expression of age onset proteotoxicity modifier genes in APP tg models. For this purpose we propose the following aims: Aim 1. To provide neuropathological analysis of in vivo and in vitro models of aging and AD. This will include analysis of AD-related neuropathology (Abeta deposition) and markers of neurodegeneration (eg: synaptophysin and PSD-95 (synapses), MAP2 (dendrites), NeuN (neurons), GFAP (astrocytes), lba-1 (microglia)) by immunocytochemistry, confocal microscopy, image analysis, stereology (Project 3), and expert evaluation of electron microscopy (Project 1). In addition and in coordination with Dr. Bannykh's laboratory at Cedars Sinai, the Core will offer cell-based immunogold analysis of cryosections to analyze APP processing and A* intracellular aggregation (Project 2). Aim 2. To provide alternative APP tg mouse models relevant to AD for studies of interactions with age related modifier genes. For this purpose the Core will maintain and breed APP tg mice for projects 1 and 3. These models represent an alternative to the PS1/APP tg model that was the only AD model proposed in the initial submission. We have in-house tg animal models that overexpress mutant forms of APP under neuronal promoters (platelet-derived growth factor-p and mThy-1). These models will be used by Project 3 for crosses with insulin growth factor (IGF)-1 signaling deficient mice and for the studies by Projects 1 and 3 of alternative age-related modifier genes using a lentiviral vector approach. Aim 3. To provide support in the production and testing in vivo in APP tg mice of age onset Abeta proteotoxicity modifier genes using lentiviral vector si/shRNA expression. In addition to supporting the construction and use of viral vectors, the Core will also provide reagents and expertise in gene knockdown by si/shRNA. Targeted attenuation of gene activity to reveal function has become a major tool to investigate age-related modifying genes. We will use lentiviral vectors to generate shRNAs capable of knocking down in APP tg mice pathways involved in Abeta proteotoxicity such as IGF receptor subtypes, heat shock proteins, alphaB-crystallin, IRE1, Foxa, Foxo and RAB-5.These viruses will be used by Projects land 3 and Cores.